To
show his gratitude, the Seljuk Sultan Kaihusrev II (Kaikosrau) gave
Ertughrul a strip of land encircling the battlefield. The land extended
from Eskic;ehir along the Sakarya (in antiquity: Sangarios) Valley.
It corresponded roughly with the Roman province of Bithynia which
the Seljuks had taken from the Byzantines about a century previously
Osman I founded a small empire there, which he called "Memalik
Osmanya", or "The Principality of Osman". He made
Bursa its capital in 1305, captured Gemlik in 1326 and thus laid
the foundations of what was to become the Ottoman Empire.

The Osmanli Kingdom of Bursa flourished quickly,
while the Empire of the Seljuks of Rum declined. Eventually the
latter was incorporated in the Ottoman Empire so that the tomb of
the Seljuks became the cradle of the Ottomans. The latter, who had
come from Khurasan, soon occupied the entire Mediterranean coast
of Asia Minor. But their expansion was not yet at an end. The goals
they had set themselves were the conquest of the Balkans and the
capture of Constantinople. This task was undertaken by Osman's son,
Sultan Orhan (1326-1359).

He had already conceived the notion of attacking
"the far bank" of the Bosporus from Bursa, although he
had established firm ties to the Emperor Johannes VI Kantakuzenos,
whose daughter he had married. In 1356 a small band of about sixty
Turks on rafts made of treetrunks lashed together with ropes landed
at Gallipoli (Gelibolu) on the European side of the Dardanelles.
That very morning the walls of the fortress had been destroyed by
an earthquake; therefore nothing prevented their entry into the
city. But the Turks' victory was not merely due to fortunate circumstances.
It resulted, rather, from the creation of a standing army which
was to make the Ottoman Empire the greatest military power of the
time. Until then the Ottoman troops had consisted of a cavalry,
which could be raised at need.